Filling listbox from ado query far slower in vb2005 than vb6. Can I speed it up?

Question

I converted some code from vb6 to vb2005 that opens a recordset and populates a listbox with about 8,000 names. It uses classic ado.

The vb6 code does it in about 0.75 of a second, the first vb2005 code does it in about 5.5 seconds while the second vb2005 code does it in about 4.5 seconds. Is there any way to improve the vb2005 performance a fair bit more?

    //vb6 code

    Dim myconn As ADODB.Connection
    Set myconn = New ADODB.Connection
    myconn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.3.51;Data Source=c:\TestDB1.mdb;Jet OLEDB:System Database=c:\TestDB1.mdw;User ID=TestDB;Password=123456;"
    myconn.Open

    Dim elap As Double
    elap = Timer

    List1.Visible = False
    List1.Clear
    Text1.Text = ""
    Text1.Refresh

    Dim myrec As New ADODB.Recordset
    Dim str1 As String
    str1 = "select * from Names"

    myrec.Open str1, myconn

    myrec.MoveFirst

    Do While myrec.EOF <> True
     List1.AddItem myrec.Fields("surname").Value & " " & myrec.Fields("firstname").Value
     myrec.MoveNext
    Loop
    List1.Visible = True
    Text1.Text = Timer - elap
   //
   //
   //vb2005 code '1st attempt 

    Dim myconn As New ADODB.Connection
    myconn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.3.51;Data Source=c:\TestDB1.mdb;Jet OLEDB:System Database=c:\TestDB1.mdw;User ID=TestDB;Password=123456;"
    myconn.Open()
    Dim elap As Double = DateTime.Now.TimeOfDay.TotalSeconds

    list1.Items.Clear()
    Text1.Text = ""
    Text1.Refresh()

    Dim myrec As New ADODB.Recordset
    Dim str1 As String = "select * from Names"

    myrec.Open(str1, myconn)

    myrec.MoveFirst()
    list1.BeginUpdate()
    Do While Not myrec.EOF

        list1.Items.Add(myrec.Fields("surname").Value + " " + myrec.Fields("firstname").Value)


        myrec.MoveNext()
    Loop
    list1.EndUpdate()
    Text1.Text = CStr(DateTime.Now.TimeOfDay.TotalSeconds - elap)


   //
   //
   // vb2005 code second attempt


    Dim myconn As New ADODB.Connection
    myconn.ConnectionString = "Provider=Microsoft.Jet.OLEDB.3.51;Data Source=c:\TestDB1.mdb;Jet OLEDB:System Database=c:\TestDB1.mdw;User ID=TestDB;Password=123456;"
    myconn.Open()
    Dim elap As Double = DateTime.Now.TimeOfDay.TotalSeconds

    list1.Items.Clear()
    Text1.Text = ""
    Text1.Refresh()

    Dim myrec As New ADODB.Recordset
    Dim str1 As String = "select * from Names"

    myrec.Open(str1, myconn)


    Dim counter As Integer = 0



    myrec.MoveFirst()
    Dim MyList As New List(Of String)
    Dim MyRow As String
    Do While Not myrec.EOF
        MyList.Add(myrec.Fields("surname").Value + " " + myrec.Fields("firstname").Value)
        myrec.MoveNext()
    Loop
    list1.BeginUpdate()
    list1.Items.AddRange(MyList.ToArray)
    list1.EndUpdate()

    Text1.Text = CStr(DateTime.Now.TimeOfDay.TotalSeconds - elap)

Answer 1

The original COM based ADO components are not supported for use within .NET use ADO.NET components instead.

BTW, Do your users find having 8000 items to choose from in a List box particulary helpful and easy to use?

Answer 2

I don't know about the performance in VB with ADO, but I had a similar issue in Delphi2010 where a query result of 80 000 string values took ages to read into a string list (Note: absolutely NO visual components connected) .

Settings like CacheSize etc. did not make any difference (i kept them in case). In the end, even though it does not seem to make sense, i tried using ADODataSet1.DisableControls and ADODataSet1.EnableControls to wrap the while loop in. That worked like a charm.

ADODataSet1.DisableControls;
while not ADODataset1.Eof do
begin
  codes.Add(adodataset1Code.Value);
  ADODataset1.Next;
end;
ADODataSet1.EnableControls;